1. Field of the Invention
This invention relates generally to an improvement in rolling shutters and, in particular, to an improved rolling shutter having slat end retainers which secure the shutter slats to the vertical side tracks for withstanding high wind velocities or resisting forced entries without disengagement of the slat ends from the track.
2. Description of the Prior Art
Rolling shutters are well known in the prior art. Typically, the shutters are used to cover windows, doors, lanais, and all other fenestrations in homes and buildings for protection against violent storms, burglars, heat and cold (as an insulator), and for privacy. Each rolling shutter is typically comprised of elongated plastic (PVC) or aluminum slats hinged together along their top and bottom edges and disposed horizontally between a pair of vertical side tracks anchored to a building which allow for vertical movement of the shutter slats into a stored rolled up position overhead. The roll diameter, therefore, of the entire slat mechanism is important so that the shutter can be rolled up into a small space out of the way when not in use. Another important aspect is that the shutter slats freely move in the vertical tracks and do not jam.
One major problem with conventional rolling shutters, especially in geographical areas where high winds (such as hurricanes) can be expected periodically or areas of high crime where forced entries can be anticipated, is the lack of structural integrity between the slats and tracks, dictated by the typical roll-up shutter design and the constraints of building aesthetics. Practical considerations in building construction also dictate rolling shutter structures inasmuch as often the shutters are mounted over windows in tall buildings several floors above the ground level, making the shutter exterior difficult to access from the building outside.
To enhance roller shutter structural integrity for specific short periods of time, such as during tropical storms, rolling shutters have employed (where accessible) storm braces which are mounted vertically at predetermined spaced lateral intervals across the shutter (front and back) to provide additional strength to prevent buckling and bowing of the slats caused by ambient pressure variations (positive and negative) generated by high winds. The problem with storm bars are that they are aesthetically undesirable, costly, and present practical mounting problems either because of their location making them inaccessible in high rise buildings for installation or removal. However, without such storm bars or reinforcement bars, force generated by high wind velocities typically push inwardly or pull outwardly (ambient pressure either positive or negative), causing the slat(s) to bow, reducing their effective length between shutter tracks forcing the slats from the side tracks. To overcome the problem of slat disengagement at wind loads required by various building codes, slat span lengths are greatly reduced, especially if storm bars are not available.
In trying to provide a shutter structure that can resist high wind velocities (pressures) without disengagement, one must always consider the roll-up nature of the shutter and the requirement that the slats do not get jammed in upward or downward movement of the slats relative to the side tracks.
The present invention overcomes the problems presented in the prior art by providing slat end retainers and a track configuration which are constructed in such a way to prevent a slat end from being disengaged from the track with the capability of withstanding extremely high winds, while at the same time allowing for conventional type operation of the rolling shutter with respect to roll-up storage. A further benefit is that the present invention does not increase noise or vibration in the engagement of the slat end retainers in the tracks. Finally, the track engagement feature in accordance with the present invention, as determined by the contour and shape of the slat end retainer, eliminates any possibility of jamming of the slats during up and down movement of the slats.
To use the present invention, a slat end retainer is placed at each end of a slat of alternating slats vertically (every other slat) or in areas of lower wind velocity expectations, every third slat. Therefore, the slat end retainers in accordance with the present invention need not be employed in every slat.